1. Field of the Invention
The present invention relates to a method of providing a cooking utensil or the like made of aluminum with a non-sticking coating of a fluorocarbon resin.
2. Description of the Prior Art
It is known to provide a fluorocarbon resin coating on a surface of a cooking pan or the like to prevent sticking of a food or the like to the surface. Since generally a fluorocarbon resin does not have a high adhesive strength to a surface of a base of a metal or the like, various methods have been proposed for adhering a fluorocarbon resin coating layer to a surface of a metal base with a sufficient strength to assure a practical use. For example, according to one of known methods, a surface of a base is mechanically or chemically roughened to raise the adhesive strength of the base. According to another known method, a primer coating material is utilized wherein a fluorocarbon resin co-exists with a substance which exhibits a high adhesive strength to a metal base. A further method has been proposed wherein various fillers are mixed in a fluorocarbon resin to be coated in order to improve the adhesion to a metal base.
A still further method is disclosed in Japanese Patent Publication No. 47-17636. According to the method, a surface of a shaped aluminum article is degreased and then enamel produced by adding an opacifier, a pigment agent, an addition agent and water to a borosilicate frit is coated on part or the entirety of the surface by spraying, thereafter the enamel is dried and baked and then a tetrafluoroethylene resin is coated on the surface of the enamel.
However, when a cooking pan with a fluorocarbon resin coating produced by any such conventional methods is actually used, there are drawbacks in that the resin coating may be partially swollen to rise from the base though it is not exfoliated. Further, if the resin coating is rubbed strongly by means of a spatula made of a metal or the like, then it is likely to be scraped to expose the surface of the base. Also, there is a problem that the coating may be damaged to likely cause foreign substances to stick to the cooking span.